Dave Downey owns a comic book store in Sacramento, California . . . and he has a replica of FRED FLINTSTONE'S car outside. The car was STOLEN back in December.

The police looked at surveillance footage and tracked down the thieves in January. Turns out it was three teenagers who'd cut the lock on the car, loaded it into a truck, then drove off.

Dave decided not to press charges . . . IF the three kids agreed to a punishment he came up with. He wanted them to dress up as characters from "The Flintstones" to help promote Free Comic Book Day . . . which just happened on Saturday.

They agreed to it . . . so on Saturday they dressed up as Fred, Barney, and Wilma, and stood on the street for NINE HOURS waving at cars, holding up signs, and getting people to come into the store.